.270 win questions

[dlove]

forgive me if I ask something stupid. I've learned everything I know about reloading from books and the internet. I hope to take advantage of some of the knowledge on this board.

rifle is a Marlin XL7S .270 22" w/Nikon Monarch UCC 3.5-10x50

I have been working on 130gr BT and 140gr BT loads in my .270 for a while now. my best 130gr load is 61.3 gr of H4831 with an average speed of 2998fps. in the hornady manual it shows a max load of 62 gr. at 61.5 gr I get an average velocity of 2966fps. why am I losing speed by adding more powder?

I've had a lot of trouble getting groups under 1" with 140gr BT. my best grouping load is 57gr of H4831 @ 2775. I'm really not happy with the velocity but it shoots .8-.9 inch groups consistently. yesterday, I shot this charge and bullet loaded with 5 different primers. winchester WLR and federal 210 pushed the round a bit faster at 2789. the real standout was federal 215M that made 2810 average and the best 140gr group this rifle has ever fired @ .662". I am aware that Mag primers are supposed to increase pressure. I figured with this light of a load it would be ok. is there a rule for how much pressures increases with primer changes? is it normal for Mag primers to shoot better groups?


thanks,

dan

 

[PJGunner]

"why am I losing speed by adding more powder?"

Every powder, regardless of burning rate has "happy place" if you will. If the charge is too light (epecially with the slow burners) they won't be happy and you could experirnce that hard to duplicate SEE or Secondary Explosion Effect. Not good. At the other end of the load cycle powder can also get very unhappy and your chronograph more or less lets you know. When I do a load work up, I graph the charge vs velocity and it gets quite interesting at times. First off, powder charges and velocity increase in a linear basis. So if you use powder "X" and the increase per grain it 50 FPS average you have an ide how well that powder is working for that cartridge, at least until you reach or surpass the max load in the manual. Again, the chronograph will tell you when you've started to get or have gone too far. velocity will either not increase with the next grain, make a wild jump in higher velocity or even give less velocity with that "overload." When any of those symtoms occur in my load work ups, I drop the charge at least one full grain, sometimes two and call that the max for that rifle.
I also measure case head and pressure ring expansion along with the graphing.
I have four rifles in .270 Win. :shock: Don't ask me how that came about, it just happened and it's one of ones I use the least. Well, at least up to now. One thing I have settled upon though. I no longr use 130 gr. bullets, have never used 140 gr. bullets and the two I do use are the 150 gr. Nosler Partition and 150 gr. Sierra Game King. Why you ask? Well I feel the 130 gr. bullets tear up too much good eating meat, the 140s are a compromise and the 150s have been the most accurate in all four rifles. I used to use 57.0 gr. of H4831 for both loads but today use a powder that been discontinued for aboutten years, Winchester's WMR. That one make the the .270 and .300 Win. Mag. sing and is showing serious promise in a .280 Rem. I'm starting to play with. When I found out it was dropped, I scrounges up every bit I could find so I have enough for like forever.
The last animal I shot with the .270 was an antelope in New Mexico in 2009. The shot was at roughly 75 yards and the bullet hit one of the last ribs on the left side and exited just behind the right shoulder. The antelope did a short 30 foot half circle and expired. Entry wound was about a half inch and the exit about one and a quarter inch. The stomach was nicked but he fell the right way so no contents leaked out. 8) I do believe that if I'd used a 130 gr. bullet, even a Nosler Partion that there would have been a bigger mess to clean up on that shot.
Anyway, I hope my explanation on how powder behaves or misbehaves made sense to you. The graphing gives you a sort of visual picture of what is happening for evey increase in powder. The suggestion to try 150 gr. bullets is just my personal opinion on what has worked best for me. Not the highest velocity compared to 130 gr. bullets but I get my best accuracy and wind bucking from the heavier bullet.
Paul B.

 

[hubcap]

dlove.what about seating depth changes ? Have you tried that. H-4831 is an excellent powder choice for 130,s or 140,s in the .270 I would suggest you pick one primer and one charge and work with seating depth changes in order to find that accuracy node your rifle likes the best.

 

[DrMike]

dlove,

Your rifle has maxed out at 61.5 grains. Adding more powder may increase pressure, but velocity will not increase in proportion. I would suspect that your standard deviation began to grow exponentially. Magnum primers do increase pressure, but the burn of the powder is also altered. There is no definite rule concerning accuracy resulting from the use of either magnum or large rifle primers.

 

[Antelope_Sniper]

"why am I losing speed by adding more powder?"

Because you have a 22" barrel.
With a 26" barrel, you would still continue to add velocity.

If your manuel is showing a 62gr max for H4831, it must be a old manuel. Modern max is typically considered to be around 60.5 for a 130gr bullet. I would suggest a new manuel.

 

[CatskillCrawler]

As stated by PJ and DM, these are the signs of hitting your max powder charge with those components and your rifle.

Because you have a 22" barrel.With a 26" barrel, you would still continue to add velocity.

If your manuel is showing a 62gr max for H4831, it must be a old manuel. Modern max is typically considered to be around 60.5 for a 130gr bullet. I would suggest a new manuel.

+1 - That is a hot load.

I struggled to increase my .270's velocity for years even though the accuracy was excellent. I accept my velocities now as normal for a 22" barrel.

 

[dlove]

manual is hornady handbook 8th edition.

I'm getting 3167 average from hornady superformance factory ammo. it shoots 2-3 inch groups at best. there has to be a way to match(or at least come close) their velocity with handloads.

 

[JD338]

manual is hornady handbook 8th edition.

I'm getting 3167 average from hornady superformance factory ammo. it shoots 2-3 inch groups at best. there has to be a way to match(or at least come close) their velocity with handloads.

Not necessarily. Often, the manufactures use powders that are not available to us.
H4831 and RL 22 are two of the best powders out there. I would focus on accuracy and be happy with the velocity your 22" barrel yeilds.
Getting 3000 fps with the 130 gr from a 22" barrel is actually pretty good. The 160+ fps difference really will not make much difference unless you are shooting past t e 500 yd marker.

JD338

 

[Antelope_Sniper]

JD is correct about H4831, and RL22. They are great powders in the .270 win, especially if you have a long barrel, say 26", but as you discovered, in the shorter barrels, they reach a point of deminishing marginal returns.

If you are looking for more velocity out of a short barrel, you might try 4350, W760, or RL 17.

 

[sask boy]

I have been shooting 130grs over IMR4350 for a lot more years than I would want to admit :wink: I have always been in that 2900 to 3000fps. With the 24" tube I am getting 3050fps and I am not pushing it real hard :shock:

Blessings,
Dan

 

[frankm]

Dlove,

I've loaded IMR4831 for many, many years in the 270 Win with 130 grain bullets and 22" barrels. I've had MOA or better in all of them, make sure bedding is right, etc. etc. and have gotten 3100 to 3150 fps. IMR 4831 always gave me 75+fps more than IMR 4350 with max. loads.

Now, with that said it usually took 58 to 58,5 grains to get there and the current data listed will show that as a couple grains over current max's....so, if you play with IMR 4831 start low and work up. Watch primers, bolt lift and if available use a chronograph. Also, Antelope_Sniper is right about H4831 and R22 liking longer barrels.... in my son's 24" Rem. 700 barrel 58.5 grains of IMR 4831 pushes close to 3200 fps and 60.5 grains of R22 gets us the same basic velocity. Both are 3/4" in his rifle.

Good Luck and work your way up. Keep us posted on your findings !

 

[dlove]

JD338, I know that is good advice.

I bought this to be a hunting rifle. in central MS its rare (on our land) to get a shot over 200. after I bought my 35 whelen, this gun doesn't see much action. the 35 has a much better scope anyway...

I'm just chasing velocity with the 130gr becase I'm running out of loads to work on.

I really like the high BC of the 140gr. I'll probably use it as my hunting load just because everyone else shoots 130s.

frank, thats interesting. my rifle is just a cheap hunting rifle. it hasn't had any modifications. I may give the IMR a try.

BTW, the 62gr load is with hornady brass. I can't get more than 61.3gr in RP or FC cases.

 

[Oldtrader3]

I have owned several .270 Winchesters in the past 50 years that range from Reminton 700's, Model 70's (both Pre 64, Featherweight (pre and post) fully stocked, 20 inch Post 64 Mannlicher's, Austrian fully stocked Mannlicher carbines (Model 1952) and Boss, Composite Model 70's that have now been converted to new Browning stocks and bottom metal.

I have never had a .270 in my entire life that would not shot MOA or better groups with Speer, Partitions, Ballistic tips and CT Silvertip's all 130 grain. They varied in velocity because of the 20-24 inch barrels but not in accuracy. I have never seen a .270 Winchester that would not shoot MOA with 130 Partitions with the right loads and I do not believe that there is such an animal on this planet!

There is not a mule deer or whitetail that has ever walked in front of my .270 of what ever type action and barrel length which has not died trying (DRT) if they were a suitable buck to shoot in the first place. I have killed upwards of 75 bucks in 50 years, most with one shot, with the .270 and have yet to lose an animal that I have shot with that caliber. I certainly can not find anything bad to say about the .270! It does the job without peer and with no muss and fuss.

 

[EOD Diver]

Howdy dlove,
I'm with OT3 in my love of the .270 Win. A long time ago a buddy and I happened into a herd of elk. I was shooting a 300 win and he was shooting his dad's hand-me-down 721 remington .270. We shot at the same time and both elk ran about 30 yards before expiring. Ever since then I've been a real fan and my love of the round grows every season I put another elk in the freezer. I've never lost an animal I've shot with it and to me it's the finest combination of flat trajectory, on-game performance, and mild recoil that's out there. I regularly ring the gong at 760 yds with my tired ol' 1949 M70 pushing my 140 AB handload behind a stout charge of IMR 7828ssc. I don't believe in unicorns or dragons, but there's something magical about a 140 AB at around 3000fps!
Happy Hunting!
Joe

 

[hubcap]

Dlove,

I've loaded IMR4831 for many, many years in the 270 Win with 130 grain bullets and 22" barrels. I've had MOA or better in all of them, make sure bedding is right, etc. etc. and have gotten 3100 to 3150 fps. IMR 4831 always gave me 75+fps more than IMR 4350 with max. loads.

Now, with that said it usually took 58 to 58,5 grains to get there and the current data listed will show that as a couple grains over current max's....so, if you play with IMR 4831 start low and work up. Watch primers, bolt lift and if available use a chronograph. Also, Antelope_Sniper is right about H4831 and R22 liking longer barrels.... in my son's 24" Rem. 700 barrel 58.5 grains of IMR 4831 pushes close to 3200 fps and 60.5 grains of R22 gets us the same basic velocity. Both are 3/4" in his rifle.

Good Luck and work your way up. Keep us posted on your findings !

My results mirror yours. Could not agree more with you and Sniper.

 

[tjen]

With work up loads as load dencity increases you find a point where velocity does not increase as much or at all. Than the next higher charge velocity gets better the ST-dev gest better and even accuracy can get better. Than there is that point where more powder gains nothing but pressure. This is assuming this is all happing with in the safe pressures levels.

I think the low powder dencities allow erattic powder burns, and as the dencity increases the powder burn get more consistant. With the medium burn rate powders I ofton find compressed loads usually have the best accuracty. Some powders pack in the case more tigthly and can benifit from the mag primer as well. That happy powder dencity most likely veries with powder burn rates and cartridge capacities. I watch the velocity trends as related to the powder charge.

In "general" I think for accuracy 90%-95% dencity works and is slightly lower than max pressure. I look for this for the best load as long as veloctiy id fine than I alter the OCL to fine tune the accuracy.

When I load for my 22" barred 270win with 100-V and 140gr bullets If I fine an accurate load from 2850-2900fps I will stop and then alter the OCL to fine tune the accuracy further. Accuracy kills and the difference between 100fps uslualy means less tha 1 inch at reasonable ranges and maybe 3" at say 300 yards.

 

[Antelope_Sniper]

BTW Dlove:

There was nothing "stupid" about your question. It's actually a deep technical question that's never answered in any of the books. The only reason we have an answer to it is that some of us love the .270 so much we own it in multiple barrel lengths, and have experimented with them over many years over a chronograph.

BTW, welcome to the forum.

 

[tjen]

About that stupid question. We all come here in the quest for knowledge and thats smart as in getting smarter. Even some one answering a question will gain from doing so.

Well stupid is a state of mind and sometimes there is no cure for it. Distance can help to keep from feeling its effects.

You hit on a higlhly technicial subject. Beyond me but I say this. Smokless powder relies on its ability to build pressure with in a contained area to work. If the area change the pressure changes. Just putting more powder in changes "things" As the bullet moves that changes the area that changes "things". Remember less powder than the listed max can produce excessive pressure too.

Watch for trends as you reload and keep asking question so when someone with better answers posts I can learn more too. I have loaded the 223rem,35rem,358win and the powder I use in them behave simular. I am loading the 221rem and its realy differant with some powders say faster lower volume powders. I hope my 270win and V-100 is as easy as my 223 loading was (first work up load at maxOCL producted a sub 1/2 MOA) MOA would be great for the 270 since deer are larger than ground squirals.

 

[RiverRider]

I've learned to think of the powder charge's action upon ignition as a wave, and the bullet as a surfer on a surfboard. A surfer doesn't want to accelerate so much that he gets out in front of the wave, and he doesn't want to mess around too close to the crest of the wave so that it outruns him and he ends up on the backside of it.

I think of it like this:

Smokeless powder is progressive in its burning characteristics. The higher the pressure the faster it burns and the faster it burns the higher the pressure. We're looking for balance. If the bullet can't accelerate fast enough to stay ahead of the crest of the pressure wave then pressure will go into overdrive and bad things will happen. If the bullet accelerates too fast initially then we'll never see enough pressure build up during ignition to get a good clean burn with complete consumption of the charge. I've read some theoretical musings that suggest that this causes the bullet to pause in the throat, and this is what causes the catastrophic secondary explosion. Could be. Maybe.

I've often wondered why there sometimes comes a point in increased powder charges that velocity begins to drop off, but there's never any doubt in my mind that I should back off! I don't run into this routinely, but I've seen it and would like to understand it better. I don't believe I've ever seen a good explanation as to how it occurs, but I know it does and fooling around in that locale is like playing touch football in a minefield---or so it seems to me.

I think the question is not only NOT stupid, but it's a very good question!

 

[RobertTX]

To second one of the other guys, I was able to get my .270 XL7 below 1 MOA with IMR 4350. I din't have my load info handy, but I was near max per the latest Hornady manual. Bullet was 130 gr. SST.